This invention is related to forage harvesters of the type having a basic processing unit and one of a number of crop feeding units, such as hay pickup units and row crop harvesting and gathering units of various configurations, detachably mounted forwardly thereof and, more particularly, to a novel throat sheet apparatus at the interface therebetween.
A forage harvester basic processing unit usually includes a rotary reel cutterhead, a plurality of opposed crop infeed rolls disposed forwardly thereof, the rolls defining a crop infeed passage therebetween to the cutterhead, and a feed roll housing opening forwardly so that the rolls may receive crops from the crop feeding unit. The crop feeding units generally articulate vertically relative to the basic unit and to this end is pivotally mounted thereto about a transverse pivot axis located adjacent the nip of the feed rolls.
Heretofore, manufacturers provided side shields which form a rearward extension of the rear discharge outlet of the crop feeding units and slide into the feed roll housing between the feed rolls and the housing side sheets to prevent material from escaping sideways to the gap between the basic unit and crop feeding unit which occurs upon articulation therebetween. Sliding the side shields into the housing can create some alignment difficulty in installing a crop feeding unit on the basic unit.
Additionally, it is not uncommon for a forage harvester to be produced in a family of different capacities by varying the width of the cutterhead and infeed rolls, as well as their housings, while retaining the rest of the structure except for increased drive capacity. However, in varying the width, either a means of varying the discharge openings of the crop feeding units is necessary to match the increased width of the feed throat or a new series of crop units must be provided.
Others have tried to solve the latter problem in a hay pickup using laterally slidable members on the back sheet of the pickup to vary the width of the discharge opening, the side sheets forming a rearward extension of these members. Aside from the adjustments and alignment difficulties involved, this only partially solves the problem since each crop feeding unit would require similar sliding members at added expense.